The present invention is directed to an apparatus and a related method for anchoring the two ends of an armored telephone cord and restraint cable assembly to both the telephone housing and the associated telephone handset.
Public telephones are used in a wide variety of locations and under a variety of conditions, and are frequently subjected to rigorous and indeed often vandalous abuse. Accordingly, it has been a practice in the public telephone industry to utilize an armored cord and restraint cable assembly for connecting the telephone handset to the associated housing. The typical telephone armored cord and restraint cable assembly comprises a central restraint cable having a tensile strength on the order of 1,000 pound test or greater, and which is surrounded by the electrical wires that extend between the housing and the handset for carrying electronic signals between them. The restraint cable and the telephone wires are surrounded with an armored sheath fabricated of a helically-wound metal strip, in order to protect the wires and facilitate the flexure of the restraint cable-wire-armored sheath combination. At one end the armored cord and restraint cable assembly extends from inside the telephone housing and to the other end into the handset. The restraint cable then extends longitudinally along the hollow handle portion of the handset, with the electrical wires being distributed to the respective transmitter and receiver ends of the handset (present industry practice uses a handset in which the armored cord and restraint cable assembly extends through the handset at the transmitter end).
One of the problems associated with a public telephone employing an armored cord and restraint cable assembly is the necessity for anchoring the two ends of the assembly both in the telephone housing and inside the handset. The anchoring of each end provides special problems dependent upon the type of public telephone in use.
U.S. Pat. No. 4,518,830 to Drexler et al discusses in detail prior art techniques used in the public telephone industry for anchoring both ends of an armored cord and restraint cable assembly. One disclosed by Drexler et al for anchoring the armored cord and restraint cable assembly inside the handset employs fixed molded upstanding walls inside the handgrip portion of the handset with a restricted opening adjacent the receiver end for holding a stop attached at the extremity of the restraint cable. (See FIG. 3 in the Drexler et al patent). A second anchoring technique taught by Drexler et al employs a removable wedge-shaped anchor which fits into the restriction at the interface between the hollow handle and the receiver end of the telephone (see FIGS. 9 and 11 of the Drexler et al patent).
Drexler et al also disclose techniques for anchoring the armored cord and restraint cable assembly inside the telephone housing, one of which is suited for the elbow arrangements found in some public telephones, particularly those frequently utilized in European and other foreign countries; in this regard, Drexler et al disclose an elbow extending the stop for the restraint cable inside the telephone housing (see FIGS. 4-7 of the Drexler et al reference).
U.S. Pat. No. 4,845,774 to Arzounian also discloses techniques for anchoring an armored cord and restraint cable assembly in both the telephone housing and the associated handset. The handset anchoring arrangement taught by Arzounian employs a shaped anchor member having a compound surface with first and second radii of curvature so as to be in substantially full surface contact with the interior surface of the handset at the junction of the handset yoke and receiver. U.S. Pat. No. 4,837,815 to Brancati also discloses an anchor for an armored cord and restraint cable assembly employing a shaped anchor at the juncture of the yoke and receiver sections of the handset; European Patent Application H 7,109,200.3 contains a corresponding disclosure of Brancati's technique.
Other prior art of interest includes the following: U.S. Pat. No. 2,200,794 to Krantz; U.S. Pat. No. 3,384,393 to Horton et al; and U.S. Pat. No. 3,290,429 to Prescott et al.